[Evolution] Undo does not work on Evolution 3.18 on Ubuntu 15.10

[Jorge <jorge13515 gmail com>]

Hi.  Undo does not work.  For example: I have just used the Paste as
Quotation feature.  When hitting Ctrl+z to undo it, Evolution instead
erased all the contents of the email.  This is frequent.  Many times
Evolution has erased content (though usually not the entire email)
when I hit Ctrl+z.

This is evolution 3.18.2-0ubuntu1~wily1 from the gnome3-staging PPA.
The machine runs Ubuntu 15.10 with a few PPAs, including gnome3 and
gnome3-staging.

I recall that this problem also occurred on evolution 3.16 from Ubuntu main.